This invention relates to a scroll compressor wherein the oil flow is improved to maximize the amount of oil retained within the compressor.
Scroll compressors are becoming widely utilized in refrigerant compression applications. In a scroll compressor, a first scroll has a base with a generally spiral wrap extending from the base. The first scroll member interfits with a second scroll also having a base with a generally spiral wrap extending from its base. The wraps of the two scrolls interfit to define compression chambers. The second scroll is caused to orbit relative to the first scroll, and as the two move relative to each other the compression chambers decrease in size. A refrigerant is trapped in the compression chambers and is compressed toward a central location on the first scroll member. As the refrigerant reaches a central location it moves through a discharge port and into a discharge pressure chamber.
Scroll compressors are typically mounted in a sealed compressor housing. The sealed compressor housings typically enclose both scrolls and an electric motor for driving the second scroll. Typically, the motor is maintained in a suction chamber which is exposed to the suction refrigerant passing to the compressor. This refrigerant assists in cooling the motor.
Some separation point is defined within the housing to separate the discharge and suction pressure chambers. Often, a separate separator plate is utilized to define the suction and discharge pressure chambers. More recently, other ways of defining the separation area between the suction and discharge pressure chamber have been developed. As one example, the first scroll base has been proposed to separate the two chambers.
Lubricant is important to the operation of a scroll compressor. Thus, an oil sump is typically provided within the sealed housing. Oil passes through the shaft which drives the second scroll, and is delivered to the interface of the first and second scrolls during compression. Thus, there is lubricant mixed with the refrigerant as it is compressed. As the compressed refrigerant leaves the compression chambers, it moves into the discharge pressure chamber. From the discharge pressure chamber, the refrigerant moves downstream to the next component in the refrigerant cycle, the condenser. However, since oil may be mixed with the refrigerant, when the refrigerant leaves the compressor, the oil may migrate with the refrigerant. This is somewhat undesirable, as it is desirable to maintain a sufficient quantity of lubricant in the compressor.
It has been proposed to place oil return lines at various locations in the scroll compressor to return lubricant to the sump. However, the proposals to date have not sufficiently separated and returned oil to the sump from the refrigerant prior to the refrigerant leaving the compressor.